Accrued Expenses And Other Liabilities (Schedule Of Accrued Expenses & Other Current Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued compensation and benefits	$ 34,955	$ 20,898
Professional services	10,835	10,900
Accrued rent and occupancy	8,535	7,335
Fulfillment, freight, and duties	6,921	14,572
Royalties payable and deferred revenue	6,193	7,475
Sales/use and value added taxes payable	3,509	4,978
Other	13,498	12,124
Total accrued expenses and other liabilities	$ 84,446	$ 78,282